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I'm using for my first time QgsMapCanvas() and when I write my script and I then run it, I don't see anything in the canvas. That's my script:

canva = QgsMapCanvas()
r = QgsRubberBand(canva,True)
points = [[QgsPointXY(607826.87000000011175871, 380922.09400000004097819),
           QgsPointXY(607846.87000000011175871, 380922.09400000004097819),
           QgsPointXY(607846.87000000011175871, 380952.09400000004097819)]]
r.setToGeometry(QgsGeometry.fromPolygonXY(points),None)

r.show()
canva.show()

Any help from you?

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  • 1
    Try just after defining r : r.setWidth(1) and r.setColor(QColor(255, 0, 0)), and canva = iface.mapCanvas().
    – J. Monticolo
    Commented Jun 28, 2021 at 9:36
  • Make it an answer I think
    – ThomasG77
    Commented Jun 28, 2021 at 9:42
  • 1
    imho the solution is setting the canvas extent
    – Ben W
    Commented Jun 28, 2021 at 9:46

1 Answer 1

Reset to default
2

You need to set the extent of your QgsMapCanvas object.

Simply add the following line:

canva.setExtent(QgsGeometry.fromPolygonXY(points).boundingBox())

By the way, if you wish to zoom out slightly from the polygon extent, you can use the method zoomByFactor()

E.g. running:

canva = QgsMapCanvas()
r = QgsRubberBand(canva,True)
points = [[QgsPointXY(607826.87000000011175871, 380922.09400000004097819),
           QgsPointXY(607846.87000000011175871, 380922.09400000004097819),
           QgsPointXY(607846.87000000011175871, 380952.09400000004097819)]]
r.setToGeometry(QgsGeometry.fromPolygonXY(points),None)
canva.setExtent(QgsGeometry.fromPolygonXY(points).boundingBox())
canva.zoomByFactor(1.1)
r.show()
canva.show()

from the Python console results in:

enter image description here

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